342 
PROFESSOR W. WILLIAMSON ON THE ORGANIZATION 
We still see the two terminal appendages, d, d. Fig. 41 represents a similar cell, 
a, but here the two terminal structures, d, d, are less regular, and their boundary 
walls are spread out into flat surfaces of cell tissue. In figs. 42 and 43 we recognise 
repetitions of fig. 39, only in the interior of the outer cell, a, we find a number 
of small spherical bodies,/’ which, in fig. 42 are seen to be enclosed within the second 
membrane, b. Figs. 44, 45, and 46, represent what, at the first glance, look like 
very different objects, but which intermediate forms demonstrate to be identical with 
the rest, only seen in different positions. W e now see that the cell, a, is a four-sided 
object exactly resembling, in all but size, an ordinary microspore of a Lepidodendron. 
This is best seen in 44 and 45, the projecting apex of the cell having, in fig. 46, been 
ground away in making the section. That this spore-shaped structure is identical with 
the cell, a, in the other figures, is shown in fig. 47, where we have the general contour 
of figs. 39 and 42, but combined with the projecting triradiate ridges, e, of figs. 44 and 
45. We thus learn that the terminal appendages, d, of the figures just described, are 
transverse sections, d' , of the large curved cell, d, seen in contact with the largest 
curvature of the spore-shaped body in figs. 44, 45, and 46. In fig. 44 the larger or 
convex border of the embracing cell is seen to be slightly keeled, which explains 
the peculiar shape of the sections of these cells as shown in figs. 39 and 42. In fig. 46, 
in addition to this cell, d, d', we find some narrower ones, g, g, so that the triquetrous, 
conical body, eg looks as if it were planted by its broad convex base upon a triangular, 
multicellular scale. This condition exists in a very large number of the examples dis- 
covered ; I have not found a solitary instance in which the spore-shaped body, a, is entirely 
detached from its cellular surroundings. However small, some fragment of the encom- 
passing cellular tissue is invariably seen adhering to it, as in fig. 44. In fig. 52, a spore, 
like fig. 44, is shown in another aspect, so that the crescentic cell, 44, d, is seen crossing 
the disk of the spore, like a flat band, 52, d', and connecting the two terminal appendages 
d, d. The peculiar mode in which these supposed spores are combined with the cells 
and portions of cells to which they are attached, receives its explanation when we 
examine the section, fig. 57, which represents one of the sporangia of fig. 55 enlarged 
50 diameters. Enclosed within this sporangium we discover nine clusters of tetraspores, 
each cluster being held together by its group of mother and sister cells. The peculiar 
triangular group of fig. 46 reappears in the clusters, g, g', of fig. 57, only each cluster has 
now its full complement of four spores. The triangular contour of each group obviously 
indicates a cluster of cells derived from a common parent cell, which has packed itself 
between other similarly derived clusters and the sporangium wall, modifying its shape 
according to the resistance its expanding elements had to encounter. Several of these 
clusters exhibit the curious crescentic cell, g', g', seen in fig. 46, d, as well as in figs. 44 
and 45. In like manner, many of the tetraspores exhibit in their interior the 
protoplasmic (?) masses seen in figs. 39, 40, and 41, c. A peculiar feature of these 
sporangia, and one in which they differ from those of all Lepidostrobi with which I am 
familiar, is them shape. They present nearly the same form and dimensions; in 
